Star-delta contactor assembly, 15 kW at 400 V
The Siemens 3RA2425-8XF32-1AC2 is a factory-assembled star-delta (wye-delta) contactor assembly from the SIRIUS family, built on an S0 frame. It ships with three contactors: two 3RT2026-1AC20 units for the line and delta legs, and one 3RT2024-1AC20 for the star leg, plus the 3RA2923-2BB1 RS assembly kit that interconnects them. This assembly saves panel wiring time versus building a star-delta starter from individual contactors and a timing relay — the mechanical interlock and power bus are pre-integrated. The S0 frame size keeps the footprint compact for 15 kW motor starting duty.
Mounting and terminal details
Dimensions: 135 mm wide, 101 mm high, 171 mm deep. Clearance distances around the unit: 6 mm upwards, forwards, downwards, and to the side; 0 mm backwards — it can sit flush against the back panel. AWG equivalents for main contacts: 2x (16...12) and 2x (14...8). The magnet coil also uses screw terminals.
Environmental and mechanical ratings
Shock resistance: 11.8 g / 5 ms and 7.4 g / 10 ms on AC supply; 15 g / 5 ms and 10 g / 10 ms on DC supply. Mechanical life of the contactor is 10,000,000 operations typical. Three instantaneous auxiliary contacts are included; no auxiliary switch extension or bus communication module is fitted as standard. RoHS compliance date is 10/01/2009. The assembly carries no built-in auxiliary switch or fieldbus interface — those are added externally if needed.